Book excerpt: What do anaesthetists do? How does anaesthesia work? What are the risks? And how does the anaesthetist know if you are really asleep? Anaesthesia is a mysterious and sometimes threatening process. In this Very Short Introduction, Aidan O'Donnell takes the reader on a tour through the whole of the modern anaesthetic practice. He begins by explaining general anaesthesia: what it is, how it is produced, and how it differs from natural sleep and other forms of unconsciousness. He goes on to consider the main categories of anaesthetic drugs, including anaesthetic vapours, intravenous agents, muscle relaxants, and analgesics, together with explanations of how they work and what their purpose is. Set against the historical background of anaesthetic and surgical practice, O'Donnell examines the large role anaesthetists play in specialised areas such as intensive care medicine, pain medicine, and childbirth; and finally, he considers the risks of anaesthesia, putting in to context that anaesthesia is a very safe process. ABOUT THE SERIES: The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subject quickly. Our expert authors combine facts, analysis, perspective, new ideas, and enthusiasm to make interesting and challenging topics highly readable.